The present invention generally relates to windows having variable transmittance light filters, and more specifically to windows including electrochromic light filters.
Variable transmittance light filters, such as electrochromic light filters, have been proposed for use in architectural windows, skylights, and in windows and sunroofs for automobiles. Such electrochromic light filters reduce the transmittance of direct or reflected sunlight during daytime through the window, while not reducing such transmittance during nighttime. Not only do such light filters reduce bothersome glare and ambient brightness, but they also reduce fading of interior materials and heat load caused by the transmittance of sunlight through the window.
Electrochromic windows have not been widely accepted commercially for several reasons. First, they tend to be very expensive due to the cost of materials required for their construction, and their complex construction makes mass production difficult. Additionally, electrochromic windows have tended to have a lower life expectancy than conventional windows due to degradation of the electrochromic materials used in the window. The combination of added cost and lower life expectancy have deterred many architects and builders from using electrochromic windows.
Accordingly, an aspect of the present invention is to provide an improved electrochromic window construction. More specifically, an aspect of the invention is to provide an electrochromic window that is easier to mass-produce and that utilizes less expensive components and lower quantities of the costlier components. Another aspect of the present invention is to provide an electrochromic window that exhibits markedly improved color stability. Still another aspect of the present invention is to provide an electrochromic window having improved thermal deflection/emission characteristics. Yet another aspect of the invention is to provide an electrochromic window having an improved seal construction.
To achieve these and other aspects and advantages a window of one embodiment of the present invention comprises a first substrate, a second substrate, a spacer for spacing and maintaining the first and second substrates in a generally parallel, spaced-apart relation, and a variable-transmittance device disposed between and spaced apart from the first and second substrates thereby defining a first chamber between the first transparent element and the variable-transmittance device, and a second chamber between the second transparent element and the variable-transmittance device. The variable-transmittance device is preferably an electrochromic device.
Another embodiment of the invention pertains to a method of making an electrochromic device that comprises the steps of (1) providing an assembly including a first substrate and a second substrate spaced apart and joined by a seal to form a sealed chamber between inner surfaces of the substrates, at least (or both) one of the first and second substrates including an aperture extending between the outer surface of the substrate and the chamber; (2) filling the chamber with an electrochromic solution or an electrolytic solution through the aperture; (3) placing a plug in the aperture; and (4) adhering a thin plate over the plugged aperture.
Another embodiment of the invention pertains to a method of making an electrochromic device comprising the steps of (1) providing a first substrate; (2) adhering a first surface of a pre-formed seal gasket onto a first surface of the first substrate proximate the periphery thereof, the seal gasket having adhesive pre-applied to a second surface opposite the first surface, and having a release liner attached to the adhesive on the second surface of the seal gasket; (3) removing the release liner from the second surface of the seal gasket; and (4) aligning a second substrate with the first substrate and pressing a first surface of the second substrate onto the adhesive on the second surface of the seal gasket.
According to yet another embodiment, a window of the present invention comprises an electrochromic medium having color stability defined as (1) a change in color xcex94E of less than 5 measured in its activated or darkened state after being exposed to 700 hours in a weatherometer while cycling; and (2) a change in color, xcex94E, of less than 5 measured in its deactivated or clear state after being exposed to 700 hours in a weatherometer while cycling, each cycle consists of applying a voltage of 1.2V for 20 sec. and 0.0V for 40 sec.
According to still yet another embodiment, a window of the present invention comprises a first substrate, a second substrate, a spacer for spacing and maintaining the first and second substrates in a generally parallel, spaced-apart relation, and first and second variable-transmittance devices disposed between the first and second substrates and spaced apart from each other. The variable transmittance devices are preferably electrochromic devices.
According to another embodiment, an electrochromic device of the present invention comprises first and second transparent elements joined by a seal in a parallel, spaced-apart relation to form a chamber therebetween, a first transparent electrode disposed over the inner surface of the first element, a second transparent electrode disposed over the inner surface of the second element, the first and second electrodes being electrically isolated from one another, an electrochromic medium disposed within the sealed chamber, a first electrical conductor electrically coupled to the first electrode about the entire perimeter of the first electrode, and a second electrical conductor electrically coupled to the second electrode about the entire perimeter of the second electrode.
According to another embodiment, an electrochromic device of the present invention comprises a first substrate and a second substrate spaced apart and joined by a seal to form a sealed chamber between inner surfaces of the substrates, the substrates being positioned to have at least a first edge generally aligned with the first edge of the other substrate, a first electrode disposed on the inner surface of the first substrate, a second electrode disposed on the inner surface of the second substrate, the first and second electrodes being electrically isolated from one another, an electrochromic medium disposed within the sealed chamber, a first electrical connector clip attached to the first electrode and to the first substrate along at least the first edge thereof, and a second electrical connector clip attached to the second electrode and to the second substrate along at least the first edge thereof, wherein the first and second electrical connector clips include a plurality of spaced-apart fingers that respectively contact the first and second electrodes, the fingers of one connector clip being spaced apart from one another by a distance greater than the width of the fingers of the other connector clip such that the fingers of the both the connector clips intermesh without physically contacting the fingers of the other connector clip. The clips may be made of steel.
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.